This invention relates to a door lock control system which allows the unlocking of the door only when the lock is operated by predetermined persons with respective predetermined keys.
For identification of the person who wishes to enter a gate or a door, it has been the conventional practice in the art to resort to one of the following methods (1) to (4):
(1) Recognition by the ratio of the lengths of five fingers of the person;
(2) Recognition by finger print of the person;
(3) Recognition by voice of the person; and
(4) Recognition by other means.
In this connection, the method (1) lacks considerations for disabled persons and involves a sanitary problem because the users have to put their five fingers on a specified contact surface.
The method (2) is difficult to propagate in view of various problems backgrounded by moral repulsion.
With regard to the method (3), the person will more or less feel perplexed to talk to a door no matter whether or not someone is in. In addition, this method is easily deceived by reproduction of recorded voice.
As for an example of the method (4), it is known to register a secret pass number on a magnetic tape of an ID (identification) card. The pass number on the ID card is read out by an input device when the card is inserted thereinto, and is collated with a keyed-in pass number. This method, however, is not reliable enough because of the easiness of duplication of the card.
Further, there is a method of using ID cards each having a photo of the card owner's face, which is to be shown to a guardman at the time of entering a gate or door. However, this method lacks reliability and efficiency because of the difficulty of identifying a card bearer by a photograph promptly within a limited time and because of easiness of preparing forged ID cards.
Under these circumstances, there is an increasing demand for a security system for checking the entrance to building, rooms or other important facilities to prevent ingression of illegal intruders including terrorists.